On Feb. 1, 2001, the Army Corps of Engineers is expected to release its final implementation plan for returning the flow of the Missouri River to more natural levels, in order to protect species and habitats along its length. Environmentalists are hailing this move, while barge operators and many farmers and others are rallying to prevent this change.

The Corps built and oversees 6 dams on the Missouri River. The master plan for seasonally controlling water flows along the river has not changed since the dams began operating as a system in 1967. The existing system is intended to maintain sufficient water levels for year-round barge operation, as well as flood prevention and control. However, regulating the river's flow in this way has disrupted habitats and has brought several species of wildlife -- including the pallid sturgeon -- to the brink of extinction.

In early December 2000, the Corps released its draft implementation plan. This provides for a "spring rise," in which water would be released from the river's dams each spring in order to build sand bars and improve fish spawning areas. But that might increase the flood risk near dams, and also make summer water levels too low for barge navigation.

In formulating this plan, the Corps collaborated closely with the Fish & Wildlife Service -- notable because the two agencies often are on opposite sides of the fence. Barring serious administrative or legal roadblocks, this plan could be implemented in Spring 2003. The proposed flow change has been a hotbed of controversy at times in the past. Likely environmental, economic and other impacts will vary widely by region -- and could also stretch into the Mississippi River, south of the two rivers' confluence.